| At present,the cement is widely used in solidified soil,However,the widespread application of cement brought about by environmental pollution problems can’t be ignored,Cement will cause air、soil and other environmental pollution during the production and use process,Therefore,to find green substitute materials for cement is an urgent problem to be solved.Rice shell ash as a by-product has the characteristic of stimulating cement activity in that to reduce the amount of cement,Similarly,mineral powder is an industrial by-product that contains chemicals similar to cement which can be used as a partial substitute for cement.In this paper,rice shell ash,mineral powder and low-doped cement are used as curing agents to analysis the effect of rice husk and mine powder on solidified soil strength and durability through indoor trial and theoretical analysis as well as the curing mechanism of both by diffraction test and scanning.The main conclusions are as follows:(1)Experimental analysis on the strength characteristics of solidified soil,the test results show that the incorporation of rice husk ash and mineral powder can significantly improve the unlimited pressure compressive strength of solidified soil;Indexed with a 7d definition compressive strength by fixed the amount of cement has been obtained from the best matching of rice shell ash and powder as 2:1;on the basis of the best ratio,the study analyzes the changes in the strength of cured soil on the basis of the best ratio.Studies have found that as the growth rate and total dules increase,the solid-limiting compressive strength of cured soil is growing,and the 7～28 intensity growth is rapid,and the growth of 28 to 90 is slow.(2)The carbonation resistance test was carried out on the cured soil samples(RS cemented soil)mixed with rice husk ash and mineral powder cured for 28 days and the control group(ordinary cemented soil).The test results showed that:With the extension of carbonation time,the carbonation depth and quality of RS soil-cement and ordinary cement are increasing,while the pH value and compressive strength are decreasing.The carbonation resistance of RS soil-cement is better than that of ordinary soil-cement.(3)The dry/wet cycle and freeze-thaw cycle test analysis of RS soil-cement and ordinary soil-cement was carried out.The test results show that the quality of RS soilcement and ordinary soil-cement is declining continuously with the increase of the number of dry/wet cycles,and the unconfined compressive strength shows a changing rule of first increasing and then decreasing.The compressive strength and mass of the two kinds of soil-cement decreased with the increase of the number of freeze-thaw cycles.After 12 freeze-thaw cycles and dry-wet cycles,the compressive strength of RS soilcement and common soil-cement decreased by 23%,43%and 7.3%,10.4%,respectively,compared with that of unrecycled samples.(4)The results show that the addition of rice husk ash and mineral powder increases the content of hydration products such as calcium silicate hydrate and calcium aluminate hydrate in the soil,and fills the pores between the soil particles to improve the integrity.As a result,the strength of the solidified soil samples is higher than that of the soil samples without rice husk ash and mineral powder.Under carbonization conditions,most of the hydration products inside the soil are hydrolyzed into calcium carbonate,which has a large volume and poor filling effect,resulting in microcracks in the volume expansion of the soil and a continuous decline in strength.(5)The improvement of the intensity of RS cement soil is mainly due to the mutual reaction of rice husk and mine powder and cement;the SiO2 and cement in rice husk and the hydrated product Ca(OH)2 of the cement produce more stable in a superimposed volcanic reaction Higher CSH,CSH has wrapping and cement effect on soil particles,enhances the compressive strength of cured soil;the rich CaO and water reactive Ca(OH)2 in the mine powder once again promoted volcanic ash reaction;rice husk ash The particle size of the mine powder is much smaller than cement particles,and the micro-collective reaction is formed inside the soil,filling the pore between the earth particles,the denseness is increased,and the pressure strength is increased.Figure[48]Table[24]Reference[83]... |
PDF Full Text Request